IOM: US likely to need bigger antiviral stockpile

Apr 25, 2008 (CIDRAP News)  The US government will need to expand its stockpile of antiviral drugs if the goal is to have enough doses to treat all patients and provide preventive treatment for some others at risk in an influenza pandemic, the Institute of Medicine (IOM) says in a report issued today.

An IOM committee of experts asserts that the government needs to clarify its goals concerning antiviral use in a pandemic, because current planning documents are fuzzy on prophylactic use of the drugs.

The nation currently has about 71 million treatment courses of antivirals in federal and state stockpiles, with a goal of 81 million courses, the report says. But in a pandemic, it might take more than twice that amount to treat sick patients and offer preventive doses to people at risk for exposure on the job, it asserts.

In other key recommendations, the IOM report says:

The Department of Health and Human Services (HHS) should launch a national effort to develop a prioritization plan for antiviral treatment and prophylaxis in a pandemic, similar to the existing program for pandemic flu vaccine allocation. The plan should be designed to be adjusted as needed during a pandemic.

Healthcare and emergency workers who are in short supply and face repeated exposure to flu should be first in line for preventive antiviral treatment in a pandemic, followed by other healthcare and emergency workers and then by household contacts of flu patients.

The government should set up a federal advisory panel, similar to the Advisory Committee on Immunization Practices, to provide advice on public health and medical responses to a pandemic, including antiviral use.

The Shelf-Life Extension Program (SLEP) for antivirals in the federal stockpilewhich extends the official shelf life for oseltamivir (Tamiflu) by 2 yearsshould be expanded to include state and private-sector antiviral stockpiles.

The government should consider using recently expired drugs that are in supplies outside the SLEP if a pandemic causes a shortage.

The 109-page report, titled Antivirals for Pandemic Influenza: Guidance on Developing a Distribution and Dispensing Program, was prepared by an eight-member committee chaired by June M. Osborn, MD, president emerita of the Josiah Macy, Jr. Foundation.

As noted in the document, health officials hope that antiviral drugs will help the nation cope during the first several months of a pandemic, when no vaccine closely matched to the emerging virus will be available. The IOM committee was assigned to recommend best practices and policies for implementing a program of treatment and prophylaxis.

However, because of the limited size of the national antiviral stockpile and the unclear goals for its use, "the committee was unable to provide specific guidance in regard to best methods and sites for dispensing," the report summary states.

Fuzzy goals"Based on federal government documents, it is not yet clear whether the goal of antiviral use is treatment, or a combination of treatment and prophylaxis," the IOM says. The Homeland Security Council's pandemic flu strategy says plans call for using antivirals only for treatment once a pandemic is under way. But HHS's pandemic flu plan gives recommendations on the use of antivirals for treatment and prophylaxis throughout a pandemic.

Accordingly, says the report, "The committee recommends that the federal government clarify the national goals for antiviral use in an influenza pandemic. If these goals include treatment of all anticipated cases and a level of prophylaxis, fiscal appropriations will be needed to expand the national stockpile to meet these goals."

The overall goal for the national stockpile is 81 million courses of antivirals, including 50 million in the federal stockpile and 31 million in state stockpiles. As of March, the federal stockpile contained 49.9 million courses, and the states had bought 21.7 million courses, for a combined total of 71.6 million, according to the IOM. About 80% to 85% of the stockpile is oseltamivir (Tamiflu), and the rest is zanamivir (Relenza).

"Providing any level of prophylaxis with existing drug supplies would require limiting the proportion to be used for treatment," the report states. For example, "Well more than twice the existing goal of 81 million [courses] would be needed to treat 25 percent of the population and provide outbreak and postexposure prophylaxis to broadly defined groups with occupational exposure."

The report says the Food and Drug Administration (FDA) last December approved Roche's application to extend the shelf life for oseltamivir in government stockpiles from 5 to 7 years. Under the FDA's SLEP, batches of drugs are tested several months before their expiration to determine their viability. But the program does not include state or other nonfederal stockpiles. In recommending that the SLEP be expanded, the IOM notes that the idea has been under discussion at HHS.

The authors also write that a pandemic could arise shortly after large state or private supplies of antivirals have expired, even though they might still be usable. Hence, the authors recommend that HHS "develop a process to use the knowledge acquired by FDA in the operation of the Shelf-Life Extension Program to facilitate the use of properly stored recently expired medications" found in supplies outside the program, if needed because of a shortage.

Some other recommendations in the report:

Public health agencies and private sector entities should develop agreements to promote trust, collaboration, and coordination concerning the use of antivirals.

The federal government, in cooperation with state, local, and tribal governments, should "support the development of a national ethical framework to guide the allocation of antivirals (and other scarce health resources) during a severe influenza pandemic."

HHS should support and fund public health agencies to develop or expand information systems for tracking who receives antivirals.

To supplement the FDA's Adverse Event Reporting System, HHS should consider additional options for gathering information about antiviral-related adverse events, such as a network of sentinel sites.